Commit d23d1248 authored by Tadeusz Struk's avatar Tadeusz Struk Committed by Jarkko Sakkinen

tpm: fix invalid locking in NONBLOCKING mode

When an application sends TPM commands in NONBLOCKING mode
the driver holds chip->tpm_mutex returning from write(),
which triggers: "WARNING: lock held when returning to user space".
To fix this issue the driver needs to release the mutex before
returning and acquire it again in tpm_dev_async_work() before
sending the command.

Cc: stable@vger.kernel.org
Fixes: 9e1b74a6 (tpm: add support for nonblocking operation)
Reported-by: default avatarJeffrin Jose T <jeffrin@rajagiritech.edu.in>
Tested-by: default avatarJeffrin Jose T <jeffrin@rajagiritech.edu.in>
Signed-off-by: default avatarTadeusz Struk <tadeusz.struk@intel.com>
Reviewed-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
parent 45477b3f
...@@ -61,6 +61,12 @@ static void tpm_dev_async_work(struct work_struct *work) ...@@ -61,6 +61,12 @@ static void tpm_dev_async_work(struct work_struct *work)
mutex_lock(&priv->buffer_mutex); mutex_lock(&priv->buffer_mutex);
priv->command_enqueued = false; priv->command_enqueued = false;
ret = tpm_try_get_ops(priv->chip);
if (ret) {
priv->response_length = ret;
goto out;
}
ret = tpm_dev_transmit(priv->chip, priv->space, priv->data_buffer, ret = tpm_dev_transmit(priv->chip, priv->space, priv->data_buffer,
sizeof(priv->data_buffer)); sizeof(priv->data_buffer));
tpm_put_ops(priv->chip); tpm_put_ops(priv->chip);
...@@ -68,6 +74,7 @@ static void tpm_dev_async_work(struct work_struct *work) ...@@ -68,6 +74,7 @@ static void tpm_dev_async_work(struct work_struct *work)
priv->response_length = ret; priv->response_length = ret;
mod_timer(&priv->user_read_timer, jiffies + (120 * HZ)); mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
} }
out:
mutex_unlock(&priv->buffer_mutex); mutex_unlock(&priv->buffer_mutex);
wake_up_interruptible(&priv->async_wait); wake_up_interruptible(&priv->async_wait);
} }
...@@ -204,6 +211,7 @@ ssize_t tpm_common_write(struct file *file, const char __user *buf, ...@@ -204,6 +211,7 @@ ssize_t tpm_common_write(struct file *file, const char __user *buf,
if (file->f_flags & O_NONBLOCK) { if (file->f_flags & O_NONBLOCK) {
priv->command_enqueued = true; priv->command_enqueued = true;
queue_work(tpm_dev_wq, &priv->async_work); queue_work(tpm_dev_wq, &priv->async_work);
tpm_put_ops(priv->chip);
mutex_unlock(&priv->buffer_mutex); mutex_unlock(&priv->buffer_mutex);
return size; return size;
} }
......
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